In a change from previous seasons, the 18 teams in the 2011 Apertura were not divided into three groups of six teams each. Instead, the eight best teams in the general table qualified for the competition.
The eight qualified teams play two games against each other on a home-and-away basis. The winner of each match up is determined by aggregate score.
The teams were seeded one to eight in quarterfinals, and will be re-seeded one to four in semifinals, depending on their position in the general table. The higher seeded teams play on their home field during the second leg.